A USA TODAY analysis found that Democratic wins in the midterms were propelled by women and well-educated voters who benefited from the booming economy. That’s the exact demographic that the upscale market – which describes itself as “America’s Healthiest Grocery Store” – caters to.

As of Thursday, in the 37 GOP districts where Democrats flipped a seat or were leading, 70 percent contain a Whole Foods Market, according to Dave Wasserman, the U.S. House editor at the nonpartisan Cook Political Report. In districts where Republicans held on or were leading, just 39 percent had one.

"Whole Foods locates its stores, in part, based on educational attainment data. They locate their stores in areas with high levels of college graduates. And that’s a good proxy for the places where Democrats are gaining vote share in the Trump era,” Wasserman said.

House Republicans ran hard on the strong economy and low employment. But USA TODAY's analysis indicates it was actually Democrats who performed well in areas that have benefited from the booming economy – areas like the suburbs of Los Angeles, Kansas City, Dallas, Minneapolis and Atlanta.

Meanwhile Democrats continued to flounder in rural areas – where the president tends to be more popular – managing to flip just five districts that are 25 percent rural or more.

"Democrats’ blue wave in the House was powered by Whole Foods districts," Wasserman said. The wave, however, had one limit: Democrats were unable to flip any House District where President Donald Trump won by over 55 percent of the vote in 2016.

"Some Democrats react to this statistic by saying they just need to build more Whole Foods markets. It's not that simple, because Whole Foods tends to follow its demographic as much as its demographic follows it,” Wasserman said.

Whole Foods, which operates 474 markets in the U.S., did not immediately respond to a request for comment. The company's CEO, John Mackey, has described himself as a Libertarian.